What is known so far about Covid-19 pills?

Pfizer pills may be the first truly effective treatment for coronavirus disease, along with molnupiravir, a drug developed by the pharmaceutical company MSD (Merck), but recently less encouraging results have been discovered about this drug. than those reported in a first phase of his experimentation.

Vaccines continue to be the only significant tool against the pandemic, which has managed to reduce the number of critical cases with Covid-19, the number of hospitalizations and deaths. The drug for Covid-19 may prove useful even in poor countries, which have very low vaccination rates.

Paxlovid

According to data published by Pfizer, if taken within three days of the onset of symptoms, Paxlovid reduces the risk of hospitalization and avoids death by 89 percent (compared with those who do not take it and develop severe forms of the disease ). If given five days after the first symptoms, the risk drops to almost 88 percent.

These results are based on a trial involving approximately 2,246 unvaccinated volunteers with characteristics similar to a high risk of developing Covid-19 symptoms. Also, according to data published by Pfizer, 0.7 percent of participants who took Paxlovid were hospitalized four weeks after the start of the trial, while no deaths were recorded. In the group of volunteers who did not take such a drug, but a substance (placebo) the percentage was at 6.5%.

Paxlovid is an antiviral that interferes with the mechanisms used by the coronavirus to multiply within the cells of infected people. Treatment consists of taking 30 tablets over five days of Paxlovid and ritonavir, another antiviral drug developed long ago against HIV. Taking this second medicine allows Paxlovid to stay active longer in the body to give better results.

In addition to high-risk patients, Pfizer is testing individuals with lower risk factors associated with Covid-19. Preliminary data released so far by the company show that the use of Paxlovid reduced the risk of hospitalization and death by 70 percent.

Clinical trials involved people who were contracted primarily with the Delta variant of the coronavirus, the most prevalent since the summer in much of the world. Pfizer, however, predicted that in some laboratory tests, the new drug has been shown to be able to fight the symptoms of Covid-19 caused by the Omicron variant as well.

Last month, Pfizer applied to the Food and Drug Administration for authorization to use Paxlovid, thanks to the first data on its efficacy and safety. The new results will be sent to the agency, which can expedite the use process, making the drug available within weeks in the United States.

Molnupiravir

In October, MSD announced that molnupiravir could reduce the risk of Covid-19 by 50 percent if taken within the first five days of the onset of Covid-19 symptoms. MSD then proceeded to test the drug and experiment with it, obtaining disappointing data from what the final analysis yielded. The efficacy of molnupiravir was in fact 30 percent and some doubts about its safety arose afterwards, to the point that they complicated the process for authorizing the pill for use by the FDA. However, a commission from the US agency had voted in favor of molnupiravir in late November, but the FDA has not yet decided on its authorization.

Molnupiravir is an oral pill, which is taken twice daily for five days. It has the ability to interfere with the processes that viruses use to multiply within cells. One of the targets is a special enzyme (polymerase) involved in transcribing viral genetic material, i.e. the instructions that the cell needs to make new copies of the virus. The drug causes the polymerase to mistype the instructions, making it impossible for the virus to reproduce.

This drug has been authorized in the UK, while the drug control authority in France has decided to reject the application for authorization submitted by the company MSD.

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